Maine
Requirements
Be a citizen of the United States;
Be at least 17 years of age (you must be at least 18 years of age to vote, except that in primary elections you may vote if you are 17 but will be 18 by the general election);
Have established and maintain a voting residence in the municipality (i.e. city, town, plantation or unorganized township) where you seek to register.
https://www.maine.gov/sos/cec/elec/voter-info/resident.html
Voter Registration Forms
Election Info
ID Required: Yes
Same-Day Registration: Yes, just Election day no early voting.
Deadlines
New Voter Registration (Deadline Dates Vary by Locality)
Request for Postal Ballot: Post received by Tue Oct 13, 2020
In-Person Request: by Tue Nov 3, 2020
Election Day Registration & Voting: Tue Nov 3, 2020
Absentee Ballot Request: Sat Oct 31, 2020
Absentee Ballot Return: Received by Tue Nov 3, 2020 8:00pm EST
In-Person Absentee: Mon Oct 12, 2020 - Thu Oct 29, 2020 8:00pm EDT